Among Liebherr’s products on display at the 2014 NordBau trade fair in Neumünster, Germany, is the PR 736 crawler tractor, a new development with a service weight of between 20 and 25 tonnes. The world premiere of the first Generation 6 crawler tractor model was in 2013 at the Bauma trade fair in Munich, Germany. The machine concept has been designed for increased efficiency and reduced fuel consumption and CO2 emissions.

Liebherr PR 736 Litronic crawler tractor extracting sand and gravel

The Liebherr crawler tractor that is on show at the NordBau trade fair is a PR 736 LGP Litronic with an operating weight of 23.4 tonnes. The front of the machine is equipped with a six-way blade with internal push frame which provides a blade capacity of 4.6m³, and the rear of the machine is equipped with a three-shank rear ripper. The undercarriage on the LGP version that is being presented has lubricated chains that are 711mm in width. In addition, the version on show is equipped with a set-up kit for GPS machine control.

The new Generation 6 models feature an electronically regulated travel drive with an integral eco-function. The driver can choose between high performance potential and maximum economy; the system automatically selected the most favourable settings for economical operation of all travel-drive components.

Proactive power control is another innovation. When a higher level of thrust is selected at the joystick, this influences the control management of the travel drive settings actively and prepares the power train for the higher performance demand. As well as responding more rapidly, the new machines offer a definite increase in performance potential.

Like all Liebherr crawler tractors and loaders, the PR 736 has hydrostatic transmission. This efficient driveline keeps engine speed at an almost constant level. The power train components and Liebherr’s intelligent engine management are ideally matched together for high efficiency and low fuel consumption.

To simplify the use of automatic machine control systems, Liebherr supplies ex-factory preparation kits for leading manufacturers’ systems; these kits are also available for Generation 6 models. Automatic machine control can maintain consistent high grading quality; less time is needed for preparation or subsequently, and data are memorised automatically.

Modern design, well-equipped new cabin

The modern design of the new Generation 6 crawler tractors, with downward-angled body panel edges and panoramic windows including the door area, provides the driver with a good all-round view of the surrounding terrain and the machine’s working attachments. The exhaust system is entirely concealed by the A-post, so that the driver’s view over the engine hood is unobstructed. Such good visibility makes operation of the machine more efficient and enhances safety during day-to-day work.

The PR 736’s cabin is a completely new development. The driver can move the ergonomically shaped travel controls to the most convenient position. An integral contact switch in the comfortable seat identifies the driver’s presence automatically, without a safety lever having to be operated. The desired travel speed can be freely preselected with no gear shifts needed, and memorised if necessary for direct selection when needed.

The touch-controlled system display for Liebherr earthmoving machines is featured on the PR 736. The touch screen is the interface for a new control architecture of modular construction and capable of almost unlimited extension. Additional options can be incorporated, for instance reversing cameras, or functions designed for extra convenience such as control of the air conditioning, and can then be shown on the display. As before, Liebherr crawler tractors can be equipped optionally with alternative operator interfaces, with an inching brake pedal or different control levers.

Modern lighting, for example high-performance LEDs, illuminates the work area effectively, even in unfavourable conditions. The modular lighting concept is integrated into the PR 736’s redesigned bodywork and can be chosen specifically to suit the tasks the machine is intended to perform.

Easy maintenance, low operating costs

Centrally located maintenance points, access flaps and engine compartment doors that open to a wide angle, a tilting cab as standard equipment and, as an option, a radiator that can be swung out for cleaning are all features that speed up and simplify servicing work on the new PR 736.

The new PR 736 has exceptionally long change intervals for operating fluids. Depending on the nature of the work, and provided that regular quality checks are performed, the hydraulic fluid change interval can be as long as 8,000 hours of operation.

Also of completely new design: the track assemblies for Generation 6 crawler tractors. The drive sprockets are of larger diameter, with more teeth in mesh, so that the operating life of both track and sprocket are extended. If working with abrasive media, track assemblies with rotary bushings are available as an option. In addition to 100% exchangeability, they prolong the replacement intervals distinctly on this type of work.

The standard Liebherr fleet management system LiDAT provides an accurate, efficient overview of essential servicing work, warning messages, the machine’s position and actual consumption data and filling levels. Depending on the agreement with the customer, the data are updated several times a day and can be called up whenever needed by means of a web browser. An automatic alarm function can also be selected, for instance if a machine leaves a predetermined zone or if a critical operating situation arises.